On Mon, Aug 20, 2018 at 04:07:28PM +0100, Daniel P. Berrangé wrote:
On Tue, Aug 14, 2018 at 01:19:42PM +0200, Michal Privoznik wrote:
In order for our drivers to lock resources for metadata change we need set of new APIs. Fortunately, we don't have to care about every possible device a domain can have. We care only about those which can live on a network filesystem and hence can be accessed by multiple daemons at the same time. These devices are covered in virDomainLockMetadataLock() and only a small fraction of those can be hotplugged (covered in the rest of the introduced APIs).
I'm not sure I understand the rationale behind saying we only care about resources on network filesystems.
If I have 2 locally running guests, and both have a serial port backed by a physical serial port, eg
<serial type="dev"> <source path="/dev/ttyS0"/> <target port="1"/> </serial>
we *do* care about locking /dev/ttyS0, as libvirtd isn't doing mutual exclusion checks anywhere else for the /dev/ttyS0 device node.
In general I think we need to lock every single file resource that is labelled for a guest, regardless of whether its local or remote.
In the next patch I propose integration into the security manager that would avoid the need to touch this domain lock abstraction at all. Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|